Waiver of interest and penalty - paying the disputed tax by the notified deadline results in conclusion of proceedings. Waiver of interest and penalty applies where the taxpayer pays the full tax demanded under certain notices, statements or orders for specified tax periods on or before the Government notified date, causing the proceedings to be deemed concluded subject to prescribed conditions; exclusions include amounts due to erroneous refunds and cases with pending appeals or writs not withdrawn, and previously paid interest or penalty is not refundable.